are you referencing a wet/dry filter with the bioballs? or is there a refugium that also houses bioballs?
My fuge is just a 30 gallon tank with some baffles and bubble calurpa with live rock that's it also have a skimmer and that is all for filtration other than my live rock in the tank
I'm assuming newguy is referring to the idea of a "refugium" full of macro algaes - basically an algae filter. IME algaes are not the most efficient or most reliable method of filtration. I know they are popular with a lot of folks these days, but personally I prefer simpler, more reliable filtration like a good skimmer, live rock and manual detritus removal.
Of course algae filtration can be (and commonly is) combined with the other methods, but personally, I've found the algae filtration to be pretty ineffective and unnecessary with the other things in place.
Refugium/algae filters work great if you are very patiant with your system (which you should be anyway). Like Chris RD said, they are commonly combined with other methods. Many pre-built refugiums come with a section that is filled with bio-balls.
I approach my filtration with the "Shot Gun" method...a little of everything spread all over. I have a bio ball/wet dry. Live rock/sand. A protien skimmer. And a UV light.
Bio-ball are good at dealing with amonia and nitrite, but produce a lot of nitrate... which refugiums can be good at dealing with. But water changes are good at dealing with it too.
There are a lot of ways to go and no one way is right or wrong, just go with what works for you and it should be all good.